SB2021031510 - Multiple vulnerabilities in Moodle
Published: March 15, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 5 vulnerabilities.
1) Improper access control (CVE-ID: CVE-2021-20283)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote user to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to improper access restrictions. The web service responsible for fetching other users' enrolled courses did not validate that the requesting user had permission to view that information in each course. A remote user can gain unauthorized access to the application.
2) Stored cross-site scripting (CVE-ID: CVE-2021-20279)
CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Green
The disclosed vulnerability allows a remote user to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data passed via the ID number user profile field. A remote user can inject and and execute arbitrary HTML and script code in user's browser in context of vulnerable website.
Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.
3) Stored cross-site scripting (CVE-ID: CVE-2021-20280)
CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Green
The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data passed via feedback answer. A remote attacker can permanently inject and execute arbitrary HTML and script code in user's browser in context of vulnerable website. Note, blind SSRF attack vector is also possible in this case.
Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.
4) Information disclosure (CVE-ID: CVE-2021-20281)
CWE-ID: CWE-200 - Exposure of sensitive information to an unauthorized actor
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote user to gain access to personal information of website users.
The vulnerability exists due to output of website users' full names via the online users block. A remote user can obtain full names of other website users.
5) Authentication bypass using an alternate path or channel (CVE-ID: CVE-2021-20282)
CWE-ID: CWE-288 - Authentication Bypass Using an Alternate Path or Channel
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to bypass authentication process.
The vulnerability exists due to an error that allowed newly created users to bypass email verification process without having an access to the verification email link/secret. A remote attacker can register an account with an email address of other users and gain unauthorized access to the application.
Remediation
Install update from vendor's website.